The Last Mile

Fibre to the Home (FTTH) deployments are expensive and not always viable for Telcos who maybe waiting 30 or 40 years to see a return on their investment. As a result some telecoms operators are adopting a more cost effective approach by deploying Fibre to the Cabinet and using the existing copper network for the last mile.

This enables Telcos to offer improved, more affordable services, more quickly because they do not need to replace the ‘last mile’ connection into homes and businesses.

The downside however, is that the bandwidth offered, whilst better than may have been available previously, is substantially restricted due to the limitations of standard DSL.

An increasingly attractive option is to deploy a hybrid solution using Fibre to the Cabinet and a DSL accelerating technology from the cabinet to the home or business premise such as VDSL2, DSL Rings, G.fast, or mBond. Each of which can be further enhanced with vectoring.

VDSL2

VDSL2 is a currently deployed standard of digital subscriber line (DSL) broadband wireline communications designed to support the wide deployment of triple play services such as voice, video, data, high-definition television (HDTV) and interactive gaming, VDSL2 is intended to enable operators and carriers to gradually, flexibly, and cost-efficiently upgrade existing xDSL infrastructure.

VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 200 Mbit/s downstream and upstream on twisted pairs using a bandwidth up to 30 MHz.

VDSL2 deteriorates quickly from a theoretical maximum of 250 Mbit/s at source to 100 Mbit/s at 0.5 km (1,600 ft) and 50 Mbit/s at 1 km (3,300 ft), but degrades at a much slower rate from there, and outperforms VDSL. Starting from 1.6 km (0.99 mi) its performance is equal to ADSL2+.

DSL Rings

DSL Rings from Genesis Technical Systems enables delivery of up to 400 Mb/s Internet bandwidth over the existing copper network in rural and urban areas.
The DSL Rings solution is composed of two components. On the physical network a Convergence Node (CN) is deployed at the distribution point to manage from 2 to 15 houses or premises. Each house is equipped with a Home Gateway (HGW). At the local exchange location, Genesis installs exchange gateway software developed to monitor all the rings deployed across the network. A full set of tools are embedded in the exchange gateway software, these include network management systems, provisioning, and auto-healing functions.

G.fast

G.fast is targeted for short loops, up to 200m from the last distribution point. G.fast technology will use the 106 MHz frequency band in the initial stage and 212 MHz in the future. The wider the frequency band, the higher bandwidth G.fast can achieve. However, higher frequencies also mean shorter transmission distances, higher costs, and greater power consumption. The frequency band that is ultimately used is a compromise between performance, costs, and implementation.

Vectoring

Although VDSL2 can ideally provide speeds up to 100 Mbit/s, it is challenging for VDSL2 to reach 100 Mbit/s access speeds due to crosstalk between lines. To address this issue, vectoring technology, which can eliminate crosstalk, was developed, raising copper access speeds to de facto rates of 100 Mbit/s. However, VDSL2 technology is a bottleneck to increasing transmission rates because vectoring technology is both a crosstalk cancelation technology and a VDSL2 technology. The maximum rate vectoring technology can reach is the maximum rate that a noiseless, single copper pair applying VDSL2 can reach.

Similar to VDSL2, G.fast performance is affected by crosstalk between lines. Without the vectoring noise cancelation process, G.fast rates are severely degraded.. This occurs because G.fast operates at a very high frequency and the impact of crosstalk on G.fast is much more severe than on VDSL2. Therefore, G.fast must use a more advanced vectoring technology to cancel crosstalk between lines.

Solutions

Genesis provides a unique solution for telecoms operators that enables them to increase the bandwidth of their broadband services by up to a multiple of twenty, up to a maximum of 400 Mb/s, upstream and downstream combined.